Im more the conspiracy guy. My reasons are numerous, but mostly its money. TV deals come with full arenas. Hockey has always been a hard sell south of the border. So you come down harder on canadian teams.
Why the Leafs more? Because you can. 99% of leagues fans love when the Leafs get suspended, and Leafs fans that get upset? Just conspiracy nuts, or homer glasses.
Now as for personal reasons there are many of those as well. Shanahan apparently made some enemies in head office when he was DOPS.
I haven't even started on the insane number of conflicts of interest the league does absolutely nothing about.
And as far as a conspiracy this isn't exactly hard to pull off. Walkom is the director of officiating. He hires and fires the refs. Theres an entire court case online with emails between Campbell and Walkom with Campbell directing him on how the League wants calls. One of the officials who didnt tow the line was fired.
The league has admitted to game management. How far of a stretch is it really to go to influencing games through officials?